1. Field of the Invention
The present invention relates to an improvement in a remote operation type damping force control mechanism for hydraulic dampers, which permits a remote operational control of the damping force of a hydraulic damper.
2. Description of Relevant Art
The damping force of a hydraulic damper is generated by hydrodynamic resistances which the hydraulic oil sealed in a cylinder of the hydraulic damper receives when passing through oil paths. Thus, the damping force is selectively controllable with a variable oil path area which causes a variation of hydrodynamic resistance.
There have been proposed various mechanisms for controlling the damping force.
For example, there is one known mechanism, in which an adjustment rod is rotatably inserted in a hollow piston rod, the adjustment rod is provided at an end part thereof with an orifice plate having a plurality of varying diameter orifices, and by rotating the adjustment rod the orifice diameter is properly selected, to thereby control the hydrodynamic resistance and thus the damping force.
The present invention particularly relates to an improvement in a remote operation type damping force control mechanism for a hydraulic damper including a damping force control mechanism of such type as described above, in which the control may be effected by a remote operation for the convenience of adjustment work, such as when the mechanism is applied to vehicles, for example.
Among conventional remote operation mechanisms for damping force control devices, there is one type in which a gear is provided at an end part of an adjustment rod, a control cable rotatable about its own axis is lead out from a remote operation part including an adjustment dial, a pinion is provided at the distal end of the control cable, and an adjustment rod is rotated through the meshing engagement between the pinion and the gear.
However, in such conventional mechanism, there is provided no allowance or play in the engagement between a pinion and a gear, with the exception of a slight backlash. Therefore, while an adjustment rod is rotated by rotating an adjustment dial in a remote operation part, a control cable has a torsion developed therein, so that the degree of rotation of the adjustment dial is not sufficiently transmitted to the adjustment rod. Moreover, when released from the operation force, the adjustment dial is to rotate in reverse to the same degree as the torsion of the control cable, thus resulting in a disadvantage in that a correct adjustment of damping force cannot be easily attained.
The present invention has been achieved to effectively eliminate such disadvantages.